Wakiso Giants started in gear in the second half of the game and in the 56th minute, Owen Baba Kasule created a beautiful pass to find Kipson Atuheire and the debutant punished the Ankole Lions at their home to give the visitors a lead.
Mbarara city created lots of chances but couldn't find the back of the net.
In the 82nd minute, the hosts were awarded a penalty, a big chance to equalize but Jude Ssemugabi hit the post and it was a goal kick.
The referee blown the final whistle as the Giants collected maximum points away from the Ankole Lions.
Debutant Atuheire Kipson only goal awarded Wakiso Giants their first league win this season in six games.
Wakiso Giants will face the 16 times champions Sc Villa in the next game at Wakisha Playground.